﻿using System;
using System.Collections.Generic;

namespace Flagwind.Plugins.Parsers
{
	public class PluginPathParser : Parser
	{
		#region 公共方法

		public override Type GetValueType(ParserContext context)
		{
			if(string.IsNullOrWhiteSpace(context.Text))
				return null;

			//处理特殊路径表达式，即获取插件文件路径或目录
			if(context.Text.StartsWith("~"))
				return typeof(string);

			var expression = PluginPath.Parse(PluginPath.PreparePathText(context.Text));
			var node = context.Node.Find(expression.Path);

			if(node != null && node.ValueType != null)
				return Reflection.MemberAccess.GetMemberType(node.ValueType, expression.Members);

			return null;
		}

		public override object Parse(ParserContext context)
		{
			if(string.IsNullOrWhiteSpace(context.Text))
				return null;

			//处理特殊路径表达式，即获取插件文件路径或目录
			if(context.Text == "~")
				return context.Plugin.FilePath;
			else if(context.Text == "~/")
				return System.IO.Path.GetDirectoryName(context.Plugin.FilePath);

			var mode = ObtainMode.Auto;
			var text = PluginPath.PreparePathText(context.Text, out mode);

			if(string.IsNullOrWhiteSpace(text))
				throw new PluginException($"Missing argument of the path parser.");

			return context.PluginContext.ResolvePath(text, context.Node, mode);
		}

		#endregion
	}
}